Title:
Educational device
United States Patent 3166856
US Patent References:
Educational device
- - 1984599

Training typewriter
- - 2613453

Data assembly apparatus
- - 2783454

Arithmetic instructing aid circuit
- - 2970386

Selective interlock mechanism
- - 3021937


Inventors:
Uttal, William R.
Publication Date:
01/26/1965
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Assignee:
IBM
Primary Class:
434/229
Other Classes:
235/145R, 400/715, 400/666, 400/84, 340/651, 400/677, 434/233, 400/74
International Classes:
G09B13/00
US Patent References:
3103073Instructor system
Foreign References:
DE153527C
GB762367A